Infinitode 2 - a strategy in the Tower Defense genre, in which the player will have to build towers to protect his base from endless waves of enemies. The game features huge maps, lots of towers, resource miners, upgrade tree and map editor.
There are options to buy premium currency, but even after the massive update last week you can still play for free and have a blast.
I remember enjoying the original on my phone a few years ago. This one doesn’t have microtransactions in it, does it?